/Engine/Plugins/Runtime/AR/Google/GoogleARCore/Source/GoogleARCoreBase/Public/GoogleARCoreAugmentedFace.h
Describes the face regions for which the pose can be queried. Left and right are defined relative to the actor (the person that the mesh belongs to).
enum EGoogleARCoreAugmentedFaceRegion { NoseTip = 0, ForeheadLeft = 1, ForeheadRight = 2, }